What conditions do halfbeaks need?

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How do you keep halfbeaks in the aquarium? Dr Heok Hee Ng has the information you need.

These depend on the halfbeaks you keep, as members of the Hemiramphidae family live in habitats ranging from very acidic peat swamps to open ocean. I’ll deal with the freshwater species here as they are more commonly encountered in the trade.

Halfbeaks generally require plenty of swimming space and a steady but not too strong current. They should be kept moderately warm at 23-27°C/73-81°F, although excessive temperatures should be avoided as they are sensitive to dissolved oxygen levels.

They are also good jumpers, which they frequently do when alarmed, so a tight-fitting lid is necessary. They can be fed a variety of live and frozen foods, including but not limited to bloodworm, Daphnia, brineshrimp and small insects such as fruit flies.

Members of the genus Hemirhamphodon (including H. pogonognathus, H. tengah and H. chrysopunctatus) typically require very soft (2 GH or less) acidic to very acidic water (pH 3.0-6.0), while those of the genus Nomorhamphus require less acidic (pH 6.5-7.5), soft to moderately hard (6-12 GH) water.  

Although Nomorhamphus can be maintained in marginally brackish water (to 1.003 sg), they, or at least N. liemi — the most common species available — are best maintained in freshwater.  

Members of the genus Dermogenys (including D. colletti, D. pusilla, D. siamensis and D. sumatrana) are hardier and tolerate a wider variety of water conditions.

Halfbeaks thrive in slightly acidic (pH 6.0-7.5), soft to moderately hard (6-12 GH) water and most do well enough in slightly brackish (sg to 1.005) conditions. They are sensitive to condition changes, particularly soon after purchase, so carefully acclimatise them.

This item was first published in the December 2009 issue of Practical Fishkeeping. It may not be reproduced without written permission.